Here’s some instructions on how to reinstall and check to make sure it’s enabled under windows:
If the Microsoft ADPCM CODEC is not listed, install it using the Add New Hardware tool in Control Panel. To do so, follow these steps:
1. Click Start, point to Settings, and then click Control Panel.
2. Double-click Add New Hardware, click Next, click No, and then click Next.
3. Click Sound, video, and game controllers, and then click Next.
4. In the Manufacturers box, find Microsoft Audio Codecs.
5. In the Models box, click the ADPCM CODEC, click Next and then click Finish.

ADPCM is a standard codec. Just re-install your system components or upgrade DirectX.